The present invention relates to a cover and holdback element for permitting disturbance-free dental operations to be performed on teeth as well as a process for the production of such a cover and holdback element and, additionally, a method for using such a cover and holdback element.
Cover and holdback elements have been known for a considerable time. The cover and holdback elements serve to provide a dentist with an adequate ergonomic access to the teeth to be treated but, as well, protect the teeth against debris generated during dental operations including, as the occasion arises, detritus of the patients themselves generated during such dental operations.
Different elements have long been in use for holding back and covering such dental work regions. Thus, the lips and cheeks of the patients can be held back from the teeth to be treated via clamps or metallic instruments, for example. A more favorable approach, in contrast, involves a holder comprising an elastic sheet, such as is disclosed, for example, in WO 03/051185 A1. In connection with this approach, two tensioning elements in the form of rings are provided between which extend a sheet. The lips of the patient are held in tension via this sheet so that the mouth opening offers sufficient access for undertaking the dental work. A similar holder is known, as well, from DE 33 29 919 A1. In connection with this holder, protection of the lips of the patient is ensured, especially for sensitive patients. Also, in connection with this lip protection, an additional unit comprised of an elastic material can be provided on the lip ridges that additionally prevents a point- or narrow area-loading of the lips. A disadvantage in this connection is, however, that the teeth themselves are unprotected so that, in particular, debris may come into contact with the teeth.
In order to offer an improved covering, it is known to deploy a so-called coffer or rubber dam that, in contrast to a lip and cheek expander, is closed off on its back side via an elastic sheet. Solely the teeth or tooth to be handled is exposed via such a rubber dam so that the remainder of the mouth volume of the patient is protected.
An example of such an approach is shown in WO 98/034 559. In an approach of this type, a sheet is provided for configuring the rubber dam, the sheet being rolled extra-orally over a frame of known construction to form the rubber dam. Additionally, a further tensioning element is provided that also holds the sheet in a tensioned condition. In accordance with the respective requirements, the dentist can also cut the sheet to conform to a particular desired location and the desired handling on the exposed tooth or the respective tooth group can then be undertaken.
It is to be understood that the deployed sheet is subjected to considerable tension due to its particular configuration. In fact, a highly elastic material such as, for example, latex, can be used for the sheet so that, in principle, it need not be feared that the sheet will rip. Such sheets can be elastically expanded, for example by a factor of 7.
Due to the expansion of the sheet, however, there occurs, on the one hand, an increase in the force that is introduced and the tensioning elements for placing the rubber dam in tension must be configured in correspondingly form stable configurations.
On the other hand, a comparatively hard configuration of these elements is frequently perceived by patients as being unpleasant, in particular if the intra-oral spanner is hard.
A certain rough accommodation of the device to the mouth of the patient can be undertaken via the use of a material reserve, as is known from the above-noted publications. In this connection, the sheet material is rolled out from the frame of the rubber dam. The dentist can then estimate the required size and correspondingly unroll the sheet material and then begin the desired treatment. The disadvantage in this connection is that a certain amount of experience is required in order to gauge the appropriate disposition of the sheet.
This problem has been known for a while whereby, for example, U.S. Pat. No. 3,406,452 discloses a rubber dam frame, whereby a band that can be adjusted via a fastening means makes possible an appropriate sizing out of the sheet, at least along general lines.
As disclosed in U.S. Pat. No. 4,215,477, a rubber dam frame having pointed projections maintains the rubber dam sheet in a suitable manner under a pre-tension. On the other hand, the known solutions are not satisfactory; either the sheet is held in too strong a tensioned condition, which is disadvantageous from several points of view, or there occur folds in the sheet, or other disadvantageous events.